Sony 24-70mm F/2.8 GM full review

The Sony FE 24-70mm F/2.8 GM is the first pro mid-range zoom lens for use with Sony’s full frame ‘E’ system; it’s the big brother of the Zeiss 24-70mm F/4 reviewed here. Being a ‘pro’ lens, it’s built very well, which also means it’s large and heavy, (2 lbs), and it doesn’t seem to balance very well on the small and lightweight Sony camera bodies, but that’s just me talking, it may feel fine to you. Sony did not incorporate OSS or optical stabilization on this lens, but your camera model may have in-body stabilization. Also included is a focus hold button, which can be customized for different uses depending on your camera model.

Fit and finish are very good. The lens appears to be clad in metal and high quality plastic with a metal mount and front filter ring area. There is a ribbed grip around the focus and zoom rings.

Sony claims the lens is ‘weather resistant’ for splashes etc, by way of a rubber gasket around the mount; however, if you look closely when the lens is mounted by shining a light behind the mount area, you can see the gasket doesn’t touch when the lens is hanging free; meaning just the weight of the lens against the camera causes a gap in the camera/lens mounting area, and the gasket does no good. Oh well, better luck on the revised version.

Sony claims the use of three aspherical elements in the design, including one ‘extreme’ aspherical element, plus two ‘ED’ elements and ‘nano AR’ coatings. Lens is made in Thailand.

Filter size is 82mm, and is so far the only ‘E’ lens that uses this size. Unfortunately, these large filters are expensive. With that said, and considering the very high quality optics on the lens, don’t use cheap ‘general brand’ filters; doing so will degrade the image quality. Go here (B&H, Amazon, eBay) for a vast selection of 82mm filters.

Focusing. This lens auto-focuses quickly and mostly accurately, (depending on your camera model), and has a very quiet linear focusing motor so it can’t be picked up when shooting video. The front filter ring doesn’t turn when focusing, so your polarizers and grads will work great. The manual focusing ring is easy to turn, and is damped properly in my opinion.

Zoom. Zooming is smooth, and requires less than a quarter turn from 24mm to 70mm. This lens has a zoom lock, and can be locked only when set to 24mm, however, I didn’t notice any zoom creep. Not a zoom issue, but notice the front element is dead flat, which is odd, check out the x-ray view. Other oddities include; when set to exactly 35mm, the exif data will read 34mm until turned well past the mark; same for 50mm, it will read 51mm. This is not a big deal, I’m just pointing it out.

In the box is the lens, front and rear caps, a black cloth padded carrying case, and a plastic petal type hood.

Distortion.

This lens has plenty of distortion, and was probably designed around in-camera digital correction, instead of optical correction. I see the typical wavy wide angle distortion at 24mm, going flat about 29-31mm, then going to pincushion distortion at 35mm all the way to 70mm. I did not enable in-camera correction so I could show the amount of actual distortion present, however, if you enable corrections, or use distortion sliders, most of the pincushion can be eliminated. Even so, unfortunately a little waviness remains near 24mm.

Maximum reproduction ratio.

Click image for larger version.

This image is a US stamp, measuring 0.87″x 1.0″ or 22mm x 25mm. The Sony FE 24-70mm F/2.8 GM has a maximum reproduction ratio of 1:4.2, which is typical for a zoom lens in this class. The close focus shot is very sharp from F/4 through F/11; this example is F/8.

Light fall-off.

24mm

70mm

Light fall-off is well controlled; I tested 24mm, 35mm, and 70mm at F/2.8, F/4, F/5.6 and F/8, and show just the wide and long end to keep you from getting too bored. I see slightly dark corners at all zoom settings, more noticeable towards the wide end, but it’s not something to worry about. I do not have an 82mm filter, so I wasn’t able to test for additional light fall-off when using a filter, however, based on testing similar lenses, I doubt it will matter much even when using a thick type filter such as a polarizer etc.

Bokeh

24mm, full view

full view

Crops from central area, click image below for larger version.

70mm, full view.

Crops from central area, click image below for larger version.

Bokeh or the character of out of focus highlight blur is about the same at all focal lengths and apertures, with a neutral looking disc, to slightly harsh looking. Distance for the 70mm samples were taken with the subject Geranium about 6′ or 2 meters from the camera. At 24mm, the distance was only about 2′, or .7 meters. It has obvious signs of aspheric element use, as concentric (onion) rings are visible especially towards the wide end if you view your images at their maximum size, at smaller sizes, it can look smooth. As always, if your subject is very close to the lens, and the background is well off in the distance, everything is blurred away, but that’s not ‘bokeh’ it’s simply background blur.

Full size resolution samples.

Feel free to download these for your personal inspection. Crop them or toggle between the images to see how sharpness changes between aperture settings.

In this Tucson, AZ mountain scene, everything is in focus, with a broad depth of field except for the very bottom of the image at wide apertures.

24mm.

The centers are very sharp, even with the aperture wide open. The mid-sections and extreme sides look good at F/2.8, but do sharpen up noticeably at F/5.6. Stopping down to F/8 provides just a hair more resolution along the periphery.

35mm.

The centers are very sharp at F/2.8, and the sides are just a bit soft. While there is little improvement along the sides at F/4, stopping down to F/5.6 maxes out the resolution across most of the image except the extreme left side, where F/8 things look very sharp.

50mm.

The centers max out at F/4, but only if you look really close, the sides are a hair soft at F/4 too. Stopping down to F/5.6 shows a barely noticeable improvement to the sides, and finally to F/8 where the whole image is very sharp, even the extreme sides.

70mm.

At 70mm, the whole image looks very good at F/2.8, but you need to stop down to F/5.6 for most of the image to max out in resolution. In this particular lens, the right side is a little soft until F/8 to F/11, and only noticeable by pixel peeping.

Conclusion.

The Sony FE 24-70mm F/2.8 GM is a superb lens, the best zoom lens Sony has ever put out, and I’ve reviewed almost all Sony lenses going back to the Konica Minolta days before Sony bought them. Impressive qualities include low light fall-off at all focal lengths, flare and ghosting are minimal, especially at wide apertures, color fringing is well controlled overall; build quality is excellent, although it is a large and heavy lens, but that’s typical of other manufacturers similar lenses. If you are looking for a smaller lens with the same focal range, check out the Sony Zeiss 24-70mm F/4, it works well also, but it’s not as sharp as the GM lens.

There are no real disappointments in either mechanical performance or optical qualities, however, I’d like to see a bit less distortion; when you correct strong distortion as this lens has especially towards the long end, it does effect the resolution when it gets fixed, although most people will never notice if you show them the final version of your image. As I pointed out earlier, the ‘weather resistant’ claim will not hold up in the real world; the gasket doesn’t mate with the mounting surface unless the camera and lens is held straight up to the sky where gravity is helping out. Also, bokeh is not really smooth at any focal length or aperture, that’s the price of having a bunch of aspherical elements in the design, although they help out with coma and contrast along the sides.

The Sony 24-70/2.8 GM is an outstanding lens, and a welcome addition to the Sony FE line-up. For those of you that don’t mind the bulk and weight of this zoom, and only want, (or can only afford) one lens, this is it! Check out the comparisons below and feel free to rid your bag of those primes lenses you thought were so good.